blowback

Meanings

1. A type of action where the pressure from the fired cartridge blows a sliding mechanism backward to extract the fired cartridge, chamber another cartridge, and cock the hammer.
2. An unintended adverse result, especially of covert political action.
3. The act of shotgunning (inhaling from a pipe etc. and exhaling into another smoker's mouth).
4. On a steam locomotive, the reversal of exhaust gases when the regulator is closed without using the blower.
5. Synonym of backscatter.

Etymology

Deverbal from blow back.